text: /**
   * \file blowfish.h
   *
   * \brief Blowfish block cipher
   *
   *  Copyright (C) 2012-2014, ARM Limited, All Rights Reserved
   *
   *  This file is part of mbed TLS (https://tls.mbed.org)
   *
   *  This program is free software; you can redistribute it and/or modify
   *  it under the terms of the GNU General Public License as published by
   *  the Free Software Foundation; either version 2 of the License, or
   *  (at your option) any later version.
   *
   *  This program is distributed in the hope that it will be useful,
   *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *  GNU General Public License for more details.
   *
   *  You should have received a copy of the GNU General Public License along
   *  with this program; if not, write to the Free Software Foundation, Inc.,
   *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
   */
  #ifndef MBEDTLS_BLOWFISH_H
  #define MBEDTLS_BLOWFISH_H
  
  #if !defined(MBEDTLS_CONFIG_FILE)
  #include "config.h"
  #else
  #include MBEDTLS_CONFIG_FILE
  #endif
  
  #include <stddef.h>
  #include <stdint.h>
  
  #define MBEDTLS_BLOWFISH_ENCRYPT     1
  #define MBEDTLS_BLOWFISH_DECRYPT     0
  #define MBEDTLS_BLOWFISH_MAX_KEY_BITS     448
  #define MBEDTLS_BLOWFISH_MIN_KEY_BITS     32
  #define MBEDTLS_BLOWFISH_ROUNDS      16         /**< Rounds to use. When increasing this value, make sure to extend the initialisation vectors */
  #define MBEDTLS_BLOWFISH_BLOCKSIZE   8          /* Blowfish uses 64 bit blocks */
  
  #define MBEDTLS_ERR_BLOWFISH_INVALID_KEY_LENGTH                -0x0016  /**< Invalid key length. */
  #define MBEDTLS_ERR_BLOWFISH_INVALID_INPUT_LENGTH              -0x0018  /**< Invalid data input length. */
  
  #if !defined(MBEDTLS_BLOWFISH_ALT)
  // Regular implementation
  //
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  /**
   * \brief          Blowfish context structure
   */
  typedef struct
  {
      uint32_t P[MBEDTLS_BLOWFISH_ROUNDS + 2];    /*!<  Blowfish round keys    */
      uint32_t S[4][256];                 /*!<  key dependent S-boxes  */
  }
  mbedtls_blowfish_context;
  
  /**
   * \brief          Initialize Blowfish context
   *
   * \param ctx      Blowfish context to be initialized
   */
  void mbedtls_blowfish_init( mbedtls_blowfish_context *ctx );
  
  /**
   * \brief          Clear Blowfish context
   *
   * \param ctx      Blowfish context to be cleared
   */
  void mbedtls_blowfish_free( mbedtls_blowfish_context *ctx );
  
  /**
   * \brief          Blowfish key schedule
   *
   * \param ctx      Blowfish context to be initialized
   * \param key      encryption key
   * \param keybits  must be between 32 and 448 bits
   *
   * \return         0 if successful, or MBEDTLS_ERR_BLOWFISH_INVALID_KEY_LENGTH
   */
  int mbedtls_blowfish_setkey( mbedtls_blowfish_context *ctx, const unsigned char *key,
                       unsigned int keybits );
  
  /**
   * \brief          Blowfish-ECB block encryption/decryption
   *
   * \param ctx      Blowfish context
   * \param mode     MBEDTLS_BLOWFISH_ENCRYPT or MBEDTLS_BLOWFISH_DECRYPT
   * \param input    8-byte input block
   * \param output   8-byte output block
   *
   * \return         0 if successful
   */
  int mbedtls_blowfish_crypt_ecb( mbedtls_blowfish_context *ctx,
                          int mode,
                          const unsigned char input[MBEDTLS_BLOWFISH_BLOCKSIZE],
                          unsigned char output[MBEDTLS_BLOWFISH_BLOCKSIZE] );
  
  #if defined(MBEDTLS_CIPHER_MODE_CBC)
  /**
   * \brief          Blowfish-CBC buffer encryption/decryption
   *                 Length should be a multiple of the block
   *                 size (8 bytes)
   *
   * \note           Upon exit, the content of the IV is updated so that you can
   *                 call the function same function again on the following
   *                 block(s) of data and get the same result as if it was
   *                 encrypted in one call. This allows a "streaming" usage.
   *                 If on the other hand you need to retain the contents of the
   *                 IV, you should either save it manually or use the cipher
   *                 module instead.
   *
   * \param ctx      Blowfish context
   * \param mode     MBEDTLS_BLOWFISH_ENCRYPT or MBEDTLS_BLOWFISH_DECRYPT
   * \param length   length of the input data
   * \param iv       initialization vector (updated after use)
   * \param input    buffer holding the input data
   * \param output   buffer holding the output data
   *
   * \return         0 if successful, or
   *                 MBEDTLS_ERR_BLOWFISH_INVALID_INPUT_LENGTH
   */
  int mbedtls_blowfish_crypt_cbc( mbedtls_blowfish_context *ctx,
                          int mode,
                          size_t length,
                          unsigned char iv[MBEDTLS_BLOWFISH_BLOCKSIZE],
                          const unsigned char *input,
                          unsigned char *output );
  #endif /* MBEDTLS_CIPHER_MODE_CBC */
  
  #if defined(MBEDTLS_CIPHER_MODE_CFB)
  /**
   * \brief          Blowfish CFB buffer encryption/decryption.
   *
   * \note           Upon exit, the content of the IV is updated so that you can
   *                 call the function same function again on the following
   *                 block(s) of data and get the same result as if it was
   *                 encrypted in one call. This allows a "streaming" usage.
   *                 If on the other hand you need to retain the contents of the
   *                 IV, you should either save it manually or use the cipher
   *                 module instead.
   *
   * \param ctx      Blowfish context
   * \param mode     MBEDTLS_BLOWFISH_ENCRYPT or MBEDTLS_BLOWFISH_DECRYPT
   * \param length   length of the input data
   * \param iv_off   offset in IV (updated after use)
   * \param iv       initialization vector (updated after use)
   * \param input    buffer holding the input data
   * \param output   buffer holding the output data
   *
   * \return         0 if successful
   */
  int mbedtls_blowfish_crypt_cfb64( mbedtls_blowfish_context *ctx,
                            int mode,
                            size_t length,
                            size_t *iv_off,
                            unsigned char iv[MBEDTLS_BLOWFISH_BLOCKSIZE],
                            const unsigned char *input,
                            unsigned char *output );
  #endif /*MBEDTLS_CIPHER_MODE_CFB */
  
  #if defined(MBEDTLS_CIPHER_MODE_CTR)
  /**
   * \brief               Blowfish-CTR buffer encryption/decryption
   *
   * Warning: You have to keep the maximum use of your counter in mind!
   *
   * \param ctx           Blowfish context
   * \param length        The length of the data
   * \param nc_off        The offset in the current stream_block (for resuming
   *                      within current cipher stream). The offset pointer to
   *                      should be 0 at the start of a stream.
   * \param nonce_counter The 64-bit nonce and counter.
   * \param stream_block  The saved stream-block for resuming. Is overwritten
   *                      by the function.
   * \param input         The input data stream
   * \param output        The output data stream
   *
   * \return         0 if successful
   */
  int mbedtls_blowfish_crypt_ctr( mbedtls_blowfish_context *ctx,
                          size_t length,
                          size_t *nc_off,
                          unsigned char nonce_counter[MBEDTLS_BLOWFISH_BLOCKSIZE],
                          unsigned char stream_block[MBEDTLS_BLOWFISH_BLOCKSIZE],
                          const unsigned char *input,
                          unsigned char *output );
  #endif /* MBEDTLS_CIPHER_MODE_CTR */
  
  #ifdef __cplusplus
  }
  #endif
  
  #else  /* MBEDTLS_BLOWFISH_ALT */
  #include "blowfish_alt.h"
  #endif /* MBEDTLS_BLOWFISH_ALT */
  
  #endif /* blowfish.h */
  